Gelatin

Gelatin is typically made using collagen from the connective tissues, tendons, ligaments, and bones of animals, most commonly pigs and cows, however, plant-based gelatin alternatives are available.

Beef gelatin can be found in a wide variety of dog foods, treats, and supplements and is one of the more popular varieties of gelatin when it comes to pet food. So, beef-derived gelatin is a no-go if your dog is also reacting to beef.